Process for manufacturing white acetate of lead solutions or crystals out of pyroligneous acid



- rnocnss ron nimurncrunrne wmrnncn'rara or LEAD sonurrons on cn'rs'rns Patented July 24, 1928.

" UNITED STATES new owner.

- MAX KLAR, E HOLZMINDEN, GERMANY.

OUT OF PYROLIGNEOUS ACID.

No Drawing. Application filed December 22, 1925,

By neutralizing crude or redi'stilled pyroligneous acid liquor with lead or lead compounds organic coloring matters w1ll be formed which contaminate and color the acetate crystals obtained by evaporating and crystallizing the neutralized liquor.

In order to obtain pure acetates, for in istance colorless sodium acetate crystals, the

' manufacture of colorless sodium acetate crystals out of pyroligneous acid can not be applied to the process for producing colorless acetate of lead crystals, because acetate of lead will be more or less decomposed before this purifying melting begins.

In the prior art relating to the manufac: ture of colorless acetate of lead crystals therefore, pyroligneous acid could not at all be employed, it was necessary to use as raw material the expensive chemical, pure acetic acid, instead of pyroligneous acid liquor.

The invention relates to an improved process for the manufacture of colorless crystals of acetate of lead, using as raw materials metallic lead or compounds of the same .and pyroligneous acid.

I have made the discovery that by heating the dry acetate of lead, even the crude acetate of lead, obtained by neutralizing the pyroligneous acid with lead or lead compounds, to a temperature, at which the organic coloring impurities become insoluble in water, but below the melting point or decomposition temperature of lead acetate, for instance at about 200-220 degrees centigrade, therefore far below its melting point, the coloring matter will be completely carbonized or transformed into compounds insoluble in water.

By dissolving in water the product which has been heated to 200 220 degrees centilead acetate.

Serial No. 77,095, and in Germany October 28, 1924.

grade the filtrate and crystallizingthe same white and pure crystals of acetate of lea will be obtained.

The procedure may be, for instance, carried out as follows: Crude or redistilled pyroligneous acid may be neutraized with metallic lead or with lead compounds giving with acetic acid, lead acetates, and evaporated to dryness. The dry mass may be, immediately or, if necessary after having been broken into pieces, heated to a temperature, at which the impurities become insoluble in water or aqueous acetate of lead solutions, but below the decomposition temperature of lead acetate. One may continue with the heating after the neutralized wood vinegar has been evaporated to dryness. A suitable temperature is between 200-220 degrees centigrade. ing de ends on the amount and the nature of the co oring'impurities. If the conversion or destructlon of the coloring organic impurities has sufiiciently proceeded, which may be determined b dissolving a sample in water and testing the solution, one allows the mass to cool, and likiviate's, if desired, after crushing or grinding, with water or with solutions of lead acetates, for'instance the mother liquors of the crystallization of The lixiviation may be carried out b thecounter current method or by the aral el current method. The solution obtalned may be treated with decoloring.

tures the organic coloring impurities become" The time of the said heatbe carried out in all insoluble in water but below the decomposition temperature of lead acetate, lixiviating the said lead acetate with water and filtering, evaporating and crystallizing the same.

2 amass 2. The process for obtaining white lead the organic coloring impurities become -in-" 10 acetate crystals or solutions of the same soluble in'water but below the decomposition from pyroligneous acid, containing or formtemperature of lead acetate, lixiviatmg with ing organic coloring impurities whicl consists aqueous solutions of lead acetate and causing 5 in neutralizing the said pyroligneous acid decolorizing agents to act on said solutions, with lead or lead compounds. making from filtering, evaporating, and crystallizin 15 the said solution, solid lead acetate, heat- In'testimony whereof I hereunto a x my ing the solid lead acetate to temperatures signature. between 200-220 degrees centigrade, at which KLAR. 

